1. Field of the invention
This invention relates to a control device for a vehicular power transmitting apparatus. The vehicular power transmitting apparatus includes an electrically controlled differential portion and a shifting portion forming part of a power transmitting path. The electrically controlled differential portion controls a differential state between the number of rotations of an input shaft connected to an internal combustion engine, and the number of rotations of an output shaft connected to drive wheels, with controlling an operating state of an electric motor connected to a rotary element of a differential portion in power trasmissive state. More particularly, the present invention relates to a technology related to the control device for ensuring a variation in drive force during a manual shift operation with the shifting portion remaining under a disabled shifting state.
2. Description of the Related Art
There has been known a vehicular power transmitting apparatus including an electrically controlled differential portion controlling a differential state between the number of rotations of an input shaft connected to an internal combustion engine, and the number of rotations of an output shaft connected to drive wheels, with controlling an operating state of an electric motor connected to a rotary element of a differential portion in power trasmissive state, and a shifting portion forming part of a power transmitting path. For instance, Patent Publication 1 (Japanese Patent Application Publication No. 2005-264762) discloses such a vehicular power transmitting apparatus. With the vehicular power transmitting apparatus disclosed in Patent Publication 1, regeneration-efficiency optimizing control means controls during a coast running condition a speed ratio of an automatic shifting portion to optimize regeneration efficiency to thereby accomplish improved fuel consumption.
By the way, when requiring a drive force or an engine bake force for a vehicle, driver usually performs a manual shift operation to effectuate, for instance, a downshift in the vehicular power transmitting apparatus. However, the shifting is restricted or limited due to various factors such as a disabled shifting state caused by a failure or another disabled shifting state resulting from an overspeed rotation or the like. For instance, the shift portion encounters a difficulty of switching a gear position or a speed ratio. In such likelihood, no decelerating drive force (engine brake) can be obtained, resulting in a probability with the occurrence of degraded operability of the vehicle.